CCAMLR

During tagging programmes for Dissostichus eleginoides at Heard and Macquarie Islands, fish have been treated with strontium to mark their otoliths for validation of subsequent age estimation. Otoliths from 69 fish that were at liberty for at least 350 days were eventually examined. Results indicate that current methods for ageing D. eleginoides are appropriate: the number of observed annuli on the otoliths after the strontium mark was consistent with the time at liberty of the fish after marking.
Current and future work on age validation is designed to address outstanding problems with age determination in this species: investigating the accuracy of ageing small fish ( 1000 days; and developing techniques to analyse the daily marks at the centre of the otolith in order to pinpoint the position of the first annulus.

The Australian longliner Eldfisk was authorised to conduct an exploratory fishery for Dissostichus sp. in CCAMLR Divisions 58.4.3b (BANZARE Bank) and Division 58.4.2 in the 2003/04 season. The results of the fisheries in Division 58.4.2 and Division 58.4.3b are summarised. Between 12 December 2003 and 23 December 2003, the Australian vessel, Eldfisk undertook exploratory longline fishing in Division 58.4.3b. 19 sets were completed, yielding 447 kg of D. eleginoides and 6345 kg of D. mawsoni. Between 6 and 25 January 2004, the vessel undertook exploratory longline fishing in Division 58.4.2, specifically in SSRUs D and E. 129 kg of D. eleginoides and 19 552 kg of D. mawsoni were caught from 46 sets.
Overall, bycatch was highest at BANZARE Bank with 916 kg of total bycatch, comprising 15% of the total catch weight. Of the two SSRUs in Division 58.4.2, bycatch was highest in SSRU E with 624 kg of total bycatch comprising around 4% of the total catch compared with 247 kg of total bycatch (4%) for SSRU D. In both SSRU’s more bycatch occurred in the research sets than in the commercial sets.

A version of the mixture fitting program CMIX was recompiled to enable it to be run within the DOS emulator of recent versions of the Microsoft Windows operating system. The performance of the recompiled version was compared with that of the original version.
The recompiled version of CMIX produced very similar, though not identical, results to the original version. We attribute this to differences in the minimisation routines of the recompiled version. We conclude that the small differences evident from these tests are unlikely to significantly influence the estimated long-term yield of Dissostichus eleginoides

The Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) has the primary competency for managing fishing south of the Antarctic Polar Front. Despite a relatively long history of scientific research and fisheries, CCAMLR’s fisheries management strategy has often had to address incomplete and uncertain information on affected resources. Fishery-independent studies are difficult and expensive to conduct. In addition, the size of the Convention Area, its remoteness and prevailing inclement weather have complicated matters. Therefore, in addition to the standard catch and effort data supplied by vessels, the collection of data by scientifically qualified observers aboard fishing vessels has assumed prominence in the collection of essential data for fisheries management purposes. The Scheme of International Scientific Observation, adopted by CCAMLR in 1992, is designed to gather and validate fishery-related information essential for assessing target species status as well as the impact of fishing on dependent and related species, including seabirds and marine mammals. The Scheme is limited to scientific observation only and is carefully separated from enforcement aspects falling covered by the CCAMLR System of Inspection. Under the Scheme observers are deployed under bilateral agreements between CCAMLR Members and they operate on vessels under flags other than their own country. This paper outlines the Scheme's history in terms of its logistics, participation and coverage, changes in research priorities, volume of data collected and data usage. The Scheme’s benefits and shortcomings are explored and an attempt is made to evaluate the total annual cost of scientific observer programs.

A new method for estimating illegal fishing effort is put forward. The results from this new method are similar to the Agnew and Kirkwood method and this suggests that the current method is adequate under circumstances of low evasion and for when good knowledge exists that zero observations reflects zero illegal fishing. The new method performs better in the case of zero detections and can potentially better handle the evasion of detection by illegal activity.
Both the new and the current method suffer from the type of observations method used, which directly affects the system. This is the prevention/detection problem, in which the greater the number of detections for a given level of illegal fishing the more often the illegal fishers will curtail their fishing trips. This leads to a negative correlation between the amount of fishing and the estimated amount of fishing, for a given number of illegal vessels.
As the number of illegal vessels increase, both the estimate and the average amount of illegal fishing increases. This gives us some confidence that the method can produce results that have a degree of legitimacy. However, the range of actual fishing (in the simulation data sets) for a given estimated level of fishing is very large. This range of uncertainty increases as the evasion rate increases.
This research suggests that it would be possible to calculate a precautionary assessment of illegal fishing such that the actual number of illegal fishing days is less than or equal to the precautionary estimate with some given level of confidence (for example 80%).

A multi-disciplinary research cruise in the Atlantic sector of the Southern Ocean was conducted during the 2004 austral winter as part of the International Collaborative Expedition to collect and study Fish Indigenous to Sub-antarctic Habitats (ICEFISH). Sampling during the ICEFISH cruise included demersal finfish, benthic invertebrates, and information of seafloor composition. The objectives of the cruise included Antarctic fish and invertebrate biochemical, molecular and physiological, ecological and population genetics research. Trawling was conducted within the CCAMLR Convention area at Shag Rocks, South Georgia, the South Sandwich Islands, and Bouvetoya Island from 5 June to 30 June, 2004. A description of demersal finfish and benthic invertebrate collections, distribution, and composition from each island group is presented, including some preliminary information on the seabed composition of shelf areas. The total number of finfish specimens recorded within the Antarctic convergence during the ICEFISH cruise trawl deployments was 9105 specimens of 29 species.
A wide contrast in finfish and invertebrate species composition between island groups was observed, with the greatest differences between the South Sandwich Islands and Bouvetoya, where the isolation of the latter island likely played a role in the different community structure. Due to mixed gear selectivity and possible avoidance, it was not feasible to make quantitative estimates of finfish abundance. However, using data from the Blake trawl, estimates of benthic invertebrate densities by station were computed and maps generated that provide information on benthic communities.

This paper summarised progress made in the BioRoss marine biodiversity research programme administered by the New Zealand Ministry of Fisheries since 2000. The objective of the BioRoss programme is to develop a more complete understanding of the biodiversity present in selected marine communities in the Ross Sea, allowing better management, and to facilitate better state of the environment reporting. This objective is being achieved by commissioning directed research on the diversity of selected marine communities within the Southern Ocean and Ross Sea.

The marine habitat exploited by black-browed Diomedea melanophyrs and grey-headed albatrosses D. chrysostoma breeding at Campbell Island, New Zealand, was studied using satellite telemetry. Data were analysed in relation to the bathymetry and sea-surface temperature of the foraging zones. Black-browed albatrosses spent 55% of their time on the Campbell Plateau but also carried out long foraging trips to the Polar Front and Antarctic Zone at a distance of over 2000 km. They relied heavily on juvenile Micromesistius australis, a schooling fish, during foraging trips to the shelf but over oceanic waters the squid Martialia hyadesi was the main prey item. Grey-headed albatrosses spend 71% of their time foraging over the deep waters of the Polar Frontal Zone where M. hyadesi comprised over 90% of the mass of prey taken. No satellite-tracked birds fed over the shelf, but data from the duration of foraging trips and dietary analysis suggests that shelf-feeding is important for this species. Significant inter-species differences in the time spent in neritic and oceanic zones show that black-browed albatrosses were reliant primarily on shelf resources while grey-headed albatrosses are primarily oceanic feeders. In addition, the 2 species overlapped little in the zones used over oceanic waters, with black-browed albatrosses feeding in more southerly waters than grey-headed albatrosses. However, both species fed on M. hyadesi when foraging in association with the Polar Front.

The numbers of Black-browed Albatrosses Diomedea melanophrys and Grey-headed Albatrosses D. chrysostoma at Campbell Island, New Zealand, have declined dramatically since the 1940s. Black-browed Albatross numbers went into a steep decline in the 1970s and, since at least 1984, have been increasing slightly at average rates of 1.1% and 2.1% per annum at two colonies. The long-term downward trend in numbers of the Grey-headed Albatross has continued into the 1990s, averaging annually between 3.0% and 4.8% per annum at different colonies. A demographic study carried out between 1984 and 1996 indicates that Black-browed and Grey-headed Albatrosses have similar high annual adult survival rates (0.945 and 0.953, respectively). Black-browed Albatrosses breed for the first time at a younger average age than do Grey-headed Albatrosses (10 years and 13.5 years, respectively), have a higher average breeding success (0.663 compared with 0.397 for the latter species) and are annual breeders where as Grey-headed Albatrosses show a typical biennial pattern of breeding. Both show low survival from fledging to first breeding; averaging 0.186 and 0.162 for Black-browed and Grey-headed Albatrosses respectively. Both species are accidentally killed in the Japanese long-line fishery for tuna Thunnus sp. In the Australasian region. The steep decline of Black-browed Albatross numbers in the 1970s was concomitant with the development of this fishery in the foraging region of the Campbell Island birds. Currently, the slight increase in numbers is due to high adult survival rates and breeding success, and is coincident with a great reduction in long-line fishing. With stable and high adult survival rates, it is expected that future population trends will be mainly influenced by the recruitment rates. The continuous decline of Grey-headed Albatrosses since the 1940s, before long-line fishing developed in this region, indicates that natural environmental processes contributed to the downward trend in breeding numbers. Modelling indicates that Grey-Headed Albatrosses numbers will continue to decrease with the present demographic parameters. A comparison between the species breeding at different sites shows that differing environmental conditions influence demographic characteristics.

Ministry of Fisheries observers reported 595 seabird captures from observed fishing operations in 2002–03: 265 from observed trawl fishing operations (67% landed dead); 113 from tuna (Thunnus spp.) longlining operations (83% landed dead); and 217 from ling (Genypterus blacodes) longline operations (95% dead). The trawl-caught seabirds were from at least eight target fisheries, four of which had less than 50 observed tows. Observed squid (Nototodarus spp.) and hoki (Macruronus novaezelandiae) trawl fisheries accounted for 87% of observed trawl-caught seabirds.
Incident rates (expressed as the percent of observed fishing operations with seabird captures) for longline fisheries in 2002–03 were highest in chartered albacore tuna (T. alalunga) sets in northern waters (17%), compared with 10% for the observed chartered southern bluefin tuna (T. maccoyii) longlines off the southwest coast of the South Island and 9% of observed ling sets. About 2% of observed hoki tows in the main fishery areas had incidental captures, compared with 9% of observed squid trawls.
Mean seabird catch rates were estimated for the main fisheries with observed seabird captures: 0.048 seabirds per 1000 hooks (s.e = 0.010) for the chartered southern bluefin tuna fishery; 0.096 seabirds per 1000 hooks (s.e. = 0.017) for the chartered albacore effort; for ling longlines, mean catch rates ranged from 0.013 seabirds per 1000 hooks (s.e. = 0.002) in LIN 4 to 0.079 (s.e. = 0.032) in LIN 3; for hoki fisheries, 0.007 seabirds per tow (s.e. = 0.008) at Cook Strait to 0.185 (s.e. = 0.103) at the Puysegur fishery; and for squid fisheries, 0.035 seabirds per tow (s.e. = 0.011) at Puysegur and 0.198 (s.e. = 0.032) off the Stewart-Snares shelf.
Total estimates are provided for the main fisheries: 42 seabirds (c.v. = 6%) were estimated caught on chartered southern bluefin tuna longlines; 94 seabirds (c.v. = 8%) were estimated from chartered albacore effort; 543 seabirds (c.v = 10%) for ling autoline fisheries in areas LIN 4, LIN 5, and LIN 6 compared with 412 seabirds (c.v. = 8%) for the six observed vessels by area and season; 269 seabirds (c.v. = 23%) for hoki fisheries at Puysegur, Sub-Antarctic, and west coast South Island; and 841 seabirds (c.v. = 12%) for squid trawl fisheries at Puysegur, Stewart-Snares shelf and SQU 6T. Numbers are given for seabirds in total, rather than individual taxa, because of problems extrapolating by seabird species over a fishery.
In fisheries for which the observer coverage was Of the reported captures, 438 were returned for identification and represented nine albatross and ten petrel taxa, one of which was previously unrecorded as caught during observed fishing operations: white-headed petrel (Pterodroma lessoni). About 75% of the seabirds returned for identification comprised four taxa: 28% were white-chinned petrels (Procellaria aequinoctialis), 18% were sooty shearwaters (Puffinus griseus), 16% were white-capped albatrosses (Thalassarche steadi), and 13% were white-chinned petrels (Procellaria aequinoctialis).